September weather forecastOtaniemi, Finland
September
Weather in September
September, the first month of the autumn in Otaniemi, is also a moderate month, with an average temperature fluctuating between 11°C (51.8°F) and 15°C (59°F).Temperature
September witnesses a gentle descent in average high-temperature, descending from August's enjoyable 19.6°C (67.3°F) to a moderate 15°C (59°F). The temperature in Otaniemi during September experiences a small drop from daytime peaks, recording an average of 11°C (51.8°F) at night.Humidity
In Otaniemi, the average relative humidity in September is 79%.Rainfall
In Otaniemi, Finland, in September, it is raining for 13.3 days, with typically 32mm (1.26") of accumulated precipitation. In Otaniemi, during the entire year, the rain falls for 144.4 days and collects up to 463mm (18.23") of precipitation.Snowfall
June through September are months without snowfall.Sea temperature
In September, the average sea temperature is 15.4°C (59.7°F).Note: Swimming becomes less enjoyable for most at a surface water temperature of 15.4°C (59.7°F). As the temperature decreases below 21°C (69.8°F), breathing becomes increasingly difficult.
Daylight
In Otaniemi, the average length of the day in September is 12h and 52min.On the first day of September, sunrise is at 06:16 and sunset at 20:24. On the last day of the month, sunrise is at 07:25 and sunset at 18:55 EEST.
Sunshine
In Otaniemi, the average sunshine in September is 7.7h.UV index
In Otaniemi, the average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for average individuals.Note: The daily high UV index of 3 during September translates into the following recommendations:
Exercise prevention - Warding off sunburn is urged. Minimize direct exposure to the Sun during midday when its radiation is at its peak. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Otaniemi, Finland
- Average high temperature in September: 15°C
The warmest month (with the highest average high temperature) is July (20.4°C).
The month with the lowest average high temperature is January (-2.2°C).
- Average low temperature in September: 11°C
The month with the highest average low temperature is July (14.5°C).
The coldest months (with the lowest average low temperature) are January and February (-5.5°C).
Average pressure in September
Otaniemi, Finland
- Average pressure in September: 1013.5mbar
The month with the highest atmospheric pressure is May (1014.9mbar).
The month with the lowest atmospheric pressure is December (1008.6mbar).
Average wind speed in September
Otaniemi, Finland
- Average wind speed in September: 16.9km/h
The windiest month (with the highest average wind speed) is December (21.1km/h).
The calmest month (with the lowest average wind speed) is May (13.7km/h).
Average humidity in September
Otaniemi, Finland
- Average humidity in September: 79%
The month with the highest relative humidity is February (91%).
The month with the lowest relative humidity is May (72%).
Average rainfall in September
Otaniemi, Finland
- Average rainfall in September: 32mm
The wettest month (with the highest rainfall) is July (51mm).
The driest month (with the least rainfall) is April (27mm).
Average rainfall days in September
Otaniemi, Finland
- Average rainfall days in September: 13.3 days
The month with the highest number of rainy days is July (16.6 days).
The month with the least rainy days is February (6.4 days).
Average snowfall in September
Otaniemi, Finland
- Average snowfall in September: 0mm
The month with the highest snowfall is January (159mm).
The months with the least snowfall are June, July, August and September (0mm).
Average snowfall days in September
Otaniemi, Finland
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (18.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Otaniemi, Finland
- Average sea temperature in September: 15.4°C
The best month for swimming (with the highest average sea temperature) is August (18.7°C).
The coldest month (with the lowest average sea temperature) is March (0.1°C).
Average daylight in September /
Average sunshine in September
Otaniemi, Finland
- Average daylight in September: 12h and 54min
The month with the longest days is June (Average daylight: 18h and 48min).
The month with the shortest days is December (Average daylight: 6h and 0min).
- Average sunshine in September: 7h and 42min
The month with the most sunshine is June (Average sunshine: 12h and 30min).
The month with the least sunshine is December (Average sunshine: 1h and 48min).
Average sunshine days in September
Otaniemi, Finland
- Average sunshine days in September: 13.5 days
The month with the most sunshine days is May (17 days).
The month with the least sunshine days is December (5.6 days).
Average UV index in September
Otaniemi, Finland
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 1).
Average cloud cover in September
Otaniemi, Finland
- Average cloud cover in September: 46
The month with the most cloud cover is December (Cloud cover 75).
The months with the least cloud cover are July and August (Cloud cover 36).
Average visibility in September
Otaniemi, Finland
- Average visibility in September: 10km
The months with the highest visibility are June, July, August and September (10km).
The months with the lowest visibility are January, February, March and December (8km).
